
A shallow, dense, fibrous mat in the top foot of soil — that mat is why nothing will grow underneath a mature one and why the surface roots ridge up through thin turf on compacted clay. It is also the species where nursery-container stem girdling roots do the most damage, so before diagnosing anything in the crown, excavate the trunk base: a straight-sided, flare-less base means a girdling root and a tree with a finite timeline.
Roughly 60-75 ft tall and 40-50 ft wide in the open, easily past 100 years in a woodlot and often 200+, though street-side in salted compacted soil many do not reach 60. At full size it is a large-tree removal — over a house or drive it means a crane or heavy rigging, near the top of the residential bracket, and the dense hard wood makes it slow to cut and process.